Evolutionarily distinct bacteriophage endolysins featuring conserved peptidoglycan cleavage sites protect mice from MRSA infection.

Abstract

OBJECTIVES:

In the light of increasing drug resistance in Staphylococcus aureus, bacteriophage endolysins [peptidoglycan hydrolases (PGHs)] have been suggested as promising antimicrobial agents. The aim of this study was to determine the antimicrobial activity of nine enzymes representing unique homology groups within a diverse class of staphylococcal PGHs.

METHODS:

PGHs were recombinantly expressed, purified and tested for staphylolytic activity in multiple in vitro assays (zymogram, turbidity reduction assay and plate lysis) and against a comprehensive set of strains (S. aureus and CoNS). PGH cut sites in the staphylococcal peptidoglycan were determined by biochemical assays (Park-Johnson and Ghuysen procedures) and MS analysis. The enzymes were tested for their ability to eradicate static S. aureus biofilms and compared for their efficacy against systemic MRSA infection in a mouse model.

RESULTS:

Despite similar modular architectures and unexpectedly conserved cleavage sites in the peptidoglycan (conferred by evolutionarily divergent catalytic domains), the enzymes displayed varying degrees of in vitro lytic activity against numerous staphylococcal strains, including cell surface mutants and drug-resistant strains, and proved effective against static biofilms. In a mouse model of systemic MRSA infection, six PGHs provided 100% protection from death, with animals being free of clinical signs at the end of the experiment.

CONCLUSIONS:

Our results corroborate the high potential of PGHs for treatment of S. aureus infections and reveal unique antimicrobial and biochemical properties of the different enzymes, suggesting a high diversity of potential applications despite highly conserved peptidoglycan target sites.

• Authors: Mathias Schmelcher, Yang Shen, Daniel C Nelson, Marcel R Eugster, Fritz Eichenseher, Daniela C Hanke, Martin J Loessner, Shengli Dong, David G Pritchard, Jean C Lee, Stephen C Becker, Juli Foster-Frey, David M Donovan
• Journal: The Journal of antimicrobial chemotherapy (J Antimicrob Chemother) Vol. 70 Issue 5 Pg. 1453-65 (May 2015) ISSN: 1460-2091 [Electronic] England
• PMID: 25630640 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: [email protected].

Chemical References

• Anti-Bacterial Agents
• Peptidoglycan
• Recombinant Proteins
• Endopeptidases
• endolysin

Topics

• Animals
• Anti-Bacterial Agents (therapeutic use)
• Bacteremia (drug therapy, microbiology)
• Bacteriophages (enzymology)
• Biological Therapy (methods)
• Cell Wall (drug effects)
• Disease Models, Animal
• Endopeptidases (genetics, metabolism, therapeutic use)
• Female
• Hydrolysis
• Methicillin-Resistant Staphylococcus aureus (drug effects)
• Mice, Inbred BALB C
• Microbial Sensitivity Tests
• Peptidoglycan (drug effects)
• Recombinant Proteins (genetics, metabolism, therapeutic use)
• Staphylococcal Infections (drug therapy, microbiology)
• Survival Analysis
• Treatment Outcome